As a growing number of airplanes scoured the southern Indian Ocean in the search for Malaysia Airlines Flight 370, authorities released new details that paint a different picture of what may have happened in the plane’s cockpit.

Military radar tracking shows that the aircraft changed altitude after making a sharp turn over the South China Sea as it headed toward the Strait of Malacca, a source close to the investigation into the missing flight told CNN. The plane flew as low as 12,000 feet at some point before it disappeared from radar, according to the source.

The sharp turn seemed to be intentional, the source said.

The official, who is not authorized to speak to the media, told CNN that the area the plane flew in after the turn is a heavily trafficked air corridor and that flying at 12,000 feet would have kept the jet well out of the way of that traffic.

Earlier Sunday, Malaysian authorities said the last transmission from the missing aircraft’s reporting system showed it heading to Beijing — a revelation that appears to undercut the theory that someone reprogrammed the plane’s flight path before the co-pilot signed off with air-traffic controllers for the last time.

That reduces, but doesn’t rule out, suspicions about foul play in the cockpit.

The new details give more insight about what happened on the plane, but don’t explain why the plane went missing or where it could be.

Missing Malaysia Airlines flight may have turned around before it vanished

Airline warns families of 239 people on board to expect the worst as search for flight MH370 widens in waters near Vietnam

Relatives of passengers on the missing Malaysia Airlines flight MH370 arrive for a meeting with airline officials in Beijing.

The Malaysia Airlines flight missing with 239 on board may have turned around just before it vanished from radar screens, the country’s air force chief said on Sunday as the government said it had contacted counter-terrorism agencies around the world.

The airline warned families to prepare for the worst as they endured a second day without news. The search of waters between Malaysia and Vietnam for any trace of flight MH370 has widened.

At least two people on the plane were travelling together on stolen passports, fuelling concerns about the Boeing-777’s abrupt disappearance in the early hours of Saturday. However, experts said there were many possible reasons for why it vanished and for people to travel on false documents.

Malaysian officials said they were looking at four suspect identities and were examining the entire passenger manifest. Interpol confirmed that at least two passports were listed in its database as stolen and that it was examining other documents.

The international police agency’s secretary general, Ronald Noble, said it had spent years urging countries to screen all passports systematically. “Now, we have a real case where the world is speculating whether the stolen passport holders were terrorists, while Interpol is asking why only a handful of countries worldwide are taking care to make sure that persons possessing stolen passports are not boarding international flights,” he said.

Two-thirds of the travellers were Chinese, while the rest were from elsewhere in Asia, North America and Europe.

The vast search area in the seas between Malaysia and Vietnam expanded further on Sunday because of the plane’s apparent turn off course. At least 40 ships and 22 aircraft from Vietnam, Malaysia, Thailand, Singapore, Indonesia, China and the United States are participating in the hunt.

The director general of the Malaysian Maritime Enforcement Agency (MMEA) said it had sent a patrol ship to gather samples from an oil slick to determine whether the oil came from the flight or a passing ship, the government-backed Bernama website reported. No debris was found nearby.
The head of the MMEA, Mohd Amdan Kurish, left, checks a radar during search for the missing plane The head of the MMEA, Mohd Amdan Kurish, left, checks a radar during the search for the missing plane. Photograph: AP

The Beijing-bound Boeing-777 had reached cruising altitude when it disappeared from radar screens around 40 minutes after taking off from Kuala Lumpur at 12.40am on Saturday. Both the airline and the aircraft model have strong safety records. The weather was generally good and the plane did not issue a distress signal.

The air force chief Rodzali Daud told a press conference that it appeared to have gone off-route. “We are trying to make sense of this … The military radar indicated that the aircraft may have made a turn back and in some parts, this was corroborated by civilian radar,” he said.

The chief executive of Malaysia Airlines, Ahmad Jauhari Yahya, said the plane had not informed the airline and air traffic control authorities of its change of course, as it was supposed to do in such circumstances.

The pilot of another flight told a Malaysian newspaper he had made brief contact with the plane via his emergency frequency at the request of Vietnamese aviation authorities who were expecting it to enter their airspace but had been unable to reach it.

The unnamed man said he was deep into Vietnamese airspace when officials asked him to relay to MH370 to establish its position, and that he succeeded at around 1.30am – around 10 minutes after the last recorded flight data.

“There [was] a lot of interference … static … but I heard mumbling from the other end,” he said, adding that he believed the voice belonged to the co-pilot, Fariq Abdul Hamid. He then lost the connection, he told the New Straits Times.

An airline pilot who flew within 100 nautical miles of the route 12 hours before the Malaysia Airline flight disappeared said there were large thunderstorms in the area, with some turbulence, but the weather did not appear to pose serious problems for commercial flights.

While the circumstances of the plane’s disappearance are extremely unusual, an Air France flight vanished without warning over the South Atlantic in 2009; investigators blamed that crash on a combination of technical problems and pilot error.

Experts also cautioned that there were various reasons why people could be on board with invalid documents.

In 2010, when an Air India Express flight overshot the runway at Mangalore, killing 160, it emerged that 10 of those on board had fraudulent passports.

One US Department of Homeland Security official told the Los Angeles Times: “Just because they were stolen doesn’t mean the travellers were terrorists.”

The passengers, using the names Luigi Maraldi and Christian Kozel, bought consecutive tickets on 6 March from China Southern, which had a codeshare agreement for the flight, paying in Thai baht. They were booked together to Beijing, where they would have had a stopover of just over 10 hours before travelling onwards to Amsterdam. “Maraldi” was then booked to fly to Copenhagen while “Kozel” was booked on a flight to Frankfurt.
Malaysian airlines search: Vietnamese air force crew stand in front of a plane Vietnamese air force crew prepare to head out from Tan Son Nhat airport to search for the Malaysian airliner. Photograph: AP

The real Maraldi and Kozel – Italian and Austrian nationals respectively – had previously reported their passports stolen in the region. Maraldi told a Thai website he lost his in a deal that went wrong at a motorcycle rental shop in Phuket.

The Malaysian transport and defence minister Hishammuddin Hussein said authorities were looking at two more possible cases of suspicious identities. “All the four names are with me and have been given to our intelligence agencies,” he said. “We are looking at all possibilities.”

No information has been issued on the other cases under review. Chinese state media reported that one of the passport numbers reported on the manifest belonged to a man from Fujian, eastern China, who was safe and well. But his name was not that listed alongside the number, which according to the manifest belonged to another Chinese man. The man told police his passport had not been lost or stolen.

An FBI team is on its way to assist the investigation because three Americans were on board. Experts from the National Transportation Safety Board – which investigates all US domestic civil aviation crashes – the Federal Aviation Administration and Boeing are also flying to the region, the NTSB said in a statement.

The CEO of a Malaysia Airlines subsidiary told reporters the plane was last inspected 10 days ago and found to be “in proper condition”.

12 days ago. A Malaysia Airlines Boeing 777 has reportedly crashed into the sea off Vietnam with 239 people on board.

State media there says the aircraft came down near Vietnam’s Tho Chu Island. Malaysian authorities
have not yet confirmed the crash and say no wreckage has been found. A search is underway.

Contact was lost two hours into the flight from Kuala Lumpur to Beijing where relatives faced an agonising wait after Flight 370 was shown to be delayed on the arrivals board.

Most of those travelling on the flight were Chinese and Malaysian but passengers were of 14 nationalities, among them Australians, Americans and French citizens.

If the crash is confirmed, it would mark the second fatal accident involving a Boeing 777 in less than a year.

Chinese authorities have stepped up security at the country’s airports, following the disappearance of a plane travelling from Kuala Lumpur to Beijing.

Malaysia Airlines flight MH370 disappeared at 02:40 local time on Saturday (18:40 GMT on Friday) with 239 people on board.

The BBC’s John Sudworth, who is in Beijing, says some Chinese media reports have criticised the delay in the informing relatives that the plane had gone missing.

Flight MH370: Pinger Locators deployed in search

Search teams have begun using towed pinger locators to hunt for the black box of missing Malaysia Airlines flight MH370.

Two ships with the locator capabilities will search a 240km (150 mile) underwater path, in the hope of recovering the plane’s data recorder.

Up to 14 planes and nine ships will also search for MH370 on Friday.

It disappeared on 8 March en route from Kuala Lumpur to Beijing. It was carrying 239 people.

It is believed to have crashed in the southern Indian Ocean, although no confirmed debris has been found from the plane.

The search is being coordinated from the city of Perth in Western Australia.

‘Highest probability’

Angus Houston, head of the Joint Agencies Coordination Centre leading the search, said that two ships had “commenced the sub-surface search for emissions from [the] black box pinger”.

Australia naval vessel Ocean Shield was using a towed pinger locator from the US Navy, while HMS Echo, which had similar capabilities, was also searching.

“The two ships will search a single 240km track converging on each other,” Air Chief Marshal Houston, who is retired, said.

The battery-powered pingers on the plane’s black box stop transmitting about 30 days after a crash, giving the searchers now perhaps only a few days.

ACM Houston said that the area had been picked on the basis of analysis of the satellite data.

It was based on work regarding “how the aircraft might have performed and how it might have been flown”, to choose the “area of highest probability as to where it might have entered the water”.

He pointed out that this data was continuing to be refined, but the current search was based on the “best data that is available”.

Given the progress in data evaluation and calculation, “there is some hope we will find the aircraft in the area we are searching”, he added.

In a statement, JACC said up to 10 military planes, four civilian planes and nine ships would be involved in Friday’s search efforts.

The focus is on a search area of about 217,000 sq km (84,000 sq miles), 1,700 km (1,000 miles) north west of Perth.

Fair weather was forecast for Friday, with visibility of around 10km (six miles), JACC said.

Meeting staff involved in the search on Friday, Australian Prime Minister Tony Abbott said: “It is probably the most difficult search that’s ever been mounted.”

“A large aircraft seems like something that would be easy enough to locate – but a large aircraft that all but disappeared and disappeared into inaccessible oceans is an extraordinary, extraordinary challenge that you’re faced with.”